Printing apparatus control system



June 4, 1963 I. w. BORUTZKE ETAL 3,092,020

PRINTING APPARATUS CONTROL SYSTEM Filed Sept. 13, 1960 5 Sheets-Sheet 1 Q INVENTORS.

IR V/N W. BORUTZKE. BYJ'OHN H. E/SENMANN.

A TTORNEY.

June 4, 1963 1. w. BORUTZKE ETAI. 3,092,020

PRINTING APPARATUS CONTROL SYSTEM 5 Sheets-Sheet 2 Filed Sept. 13, 1960 INVENTORS. IRV/N 14 .BOFUTZKE. J'OHN H-E/SENMANN.

ATTORNEY.

June 4, 1963 l. w. BORUTZKE EI'AI. 3,

PRINTING APPARATUS CONTROL SYSTEM Filed Sept. 13, 1960 5 Sheets-Sheet 3 Fig.3.

INVENTORS. lRV/N W. BOPUTZKE. JOHN H. E/SENMANN ATTORNEY.

June 4, 1963 w. BORUTZKE ETAL 3,

PRINTING APPARATUS CONTROL SYSTEM Filed Sept. 13, 1960 5 Sheets-Sheet 4 c01 .'7 60/..6. c0z .5'. COL.4. COL.3. COL.2. COL.1

IN V EN TORS'.

COL.8.

lRV/N WBORUTZKE. JOHN H- E ISE NMANN.

A TTORNE'Y.

June 4, 1963 w. BORUTZKE ETAL 3,092,020

PRINTING APPARATUS CONTROL SYSTEM Filed Sept. 15, 1960 5 Sheets-Sheet 5 'g. YA.

INVENTORS. IRV/N W. BORUTZKE. J'OHN H. E/SENMANN.

ATTQRNEY- United States "atent 3,092,020 PRINTING APPARATUS CONTROL SYSTEM Irvin W. Borutzke, Detroit, and John H. Eisenmann, Farmington, Mich., assignors to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Sept. 13, 1960, Ser. No. 55,640 7 Claims. (Cl. 101-93) This invention relates generally to printing apparatus and particularly to control systems therefor.

It is an object of the invention to provide an improved verification system for controlling operation of printing mechanism in response to both the actual positions of rotatable print wheels of the apparatus and indexed ones of selective keyboard operated switches that control the positioning of the wheels.

Another object of the invention is to provide for a printing apparatus having individually rotatable print wheels, an improved system for selectively stopping the wheels in accordance with selected keyboard operated switches to present corresponding print elements of the wheels to a printing platen.

A further object of the invention is to provide print wheel selection and verification systems directly interconnected so that there need not be any appreciable delay between the operation of positioning the print wheels and the operation of verifying the positions of the wheels with respect to the indexed ones of the key operated switches.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying five sheets of drawings in which:

FIG. 1 is a fragmentary plan view of a printing apparatus;

FIG. 2 is a view partly in elevation and partly in section, taken along the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary vertical sectional view of FIG. 1 having parts shown in elevation;

FIG. 4 is an enlarged vertical sectional view, taken along the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary end view of one of a number of print wheels of the printing apparatus;

FIG. 6 is an enlarged vertical sectional view, taken along the line 6-6 of FIG. 4; and

FIGS. 7 and 7a are component parts of a diagrammatic illustration of the printing apparatus including its control system and circuitry therefor.

Referring to the drawings by characters of reference, the printing apparatus includes a bank of print wheels 10 mounted to rotate individually and freely on a fixed shaft 12 that extends horizontally between and is supported on one of a pair of spaced apart upright supporting plates 13. The print wheels 10 respectively represent the different ones of the denominations of the decimal system. Each of the print wheels 10 has a number of radially and equally spaced teeth 14, there being eleven of such teeth on each wheel of the present printer. On the ends of ten of the teeth 14 are provided printing elements corresponding to the numeric digits to 9 inclusive, the end of the eleventh tooth being a blank or without a printing element, as shown in FIG. and designated by the numeral 15.

In mesh respectively with the print wheels are readin wheels 16 which are larger in diameter than the print wheels 10, the ratio preferably being 2 to 1. The read-in wheels 16 are individually mounted on a driven shaft 18 on which there is a normally disengaged clutch 20 comprising, in general, a continuously rotating driving component 21 that normally rotates freely on the driven shaft 18 and a driven component 22 that is fixed to the driven shaft. A continuously rotating driving shaft 23 drives the clutch component 21, such as, by means of suitable gears 22' and a driving belt 23, as shown in FIGS. 1 and 2. Projecting externally of the casing of normally engaged clutch 20 there is a clutch operating arm 24 that is operable to control operation of the clutch. The clutch 20 is positioned between a pair of stop lugs 25 and 26 on a slide 27 that is slidably supported and guided on oppositely disposed pins 28, secured to and projecting inwardly from one of the supporting plates 13. Thestop lugs 25 and 26 are spaced apart such that only one of them is in the path of the revolving clutch operating arm 24 at a time. When the stop lug 25 is engaged by the clutch operating arm 24, the read-in wheel 16 and therefore the print wheel 10 are in their home or starting positions, as shown. When the slide 27 is shifted to the left, facing FIG. 1, the arm 24 is released by the lug 25 to effect engagement of the clutch and at the same time the other lug 26 is moved into the path of revolution of the clutch operating arm 24 for engagement thereby to effect disengagement of the clutch so as to limit rotation of the read-in wheel 16 to a one-half revolution and consequently print wheel 10 to one revolution of operation. Any suitable type of clutch may be used, such as the clutch shown and described in the patent to Thomas M. Butler No. 2,629,549. As will be hereinafter more fully understood, in operation, when the slide 27 is returned to its starting position shown, the driven shaft 18 is rotated another one-half revolution which returns the read-in wheels 16 and, thus, the print wheels 10 to their home or starting positions.

Each of the read-in wheels 16 is connected to the driven shaft 18 by a slip clutch including a hub-like clutch member 28 that is fixed onto the driven shaft 18 by a pin 29, as shown in FIG. 4. The read-in wheel 16 has a hub 30 which receives an end portion of reduced diameter of member 23 which has a radially extending bore wherein an outwardly urged spring pressed detent or ball 31 normally clutches the read-in wheel 16 to the driven shaft 18. The ball detent 31 is adapted to engage alternately in a pair of V-shaped diametrically disposed recesses 32 as the read-in wheel 16 rotates through one-half revolutions. The recesses 32 are provided in the read-in wheel hub 30 and cooperate with the ball detent 31 to releasably hold the read-in wheel to shaft 18. A collar 33 is fixed by a set screw 34 to shaft 18 in abutting relation to the clutch component 22 to retain the read-in wheel 16 on the clutch member 28.

A retractable stop member or slide 36 is normally in position to stop the read-in wheel 16- and therefore the print wheel 10 in home or starting position. In this position, the blank tooth 15 of the print wheel teeth 14 is at the print line, or is in printing relation to a movable printing means or platen 38 (see FIG. 7). The stop slide 36 is urged to its stop position by a spring 40, and in this position is in the path of one of a pair of diametrically oppositely disposed abutments or pins 42, 44 that are fixed to and extend laterally from one side of the read-in wheel 16. A cam 46 on a driven cam shaft 48 is provided for retracting all of the homing slides 36 through an operating lever 49 that carries a transverse rod 50 which engages in slots in all of the homing slides. The cam 46 has a high cam portion as at 46, that extends around almost one-half of the cam to hold the homing slides 36 retracted for substantially one-half revolution of the cam.

A normally disengaged clutch 52 is operable when activated to connect the driven shaft 48 to the continuously rotating driving shaft 23. The clutch 52 is similar to the previously described clutch 20 and may be of the type disclosed in the above-mentioned patent to Thomas M. Butler No. 2,629,549. The clutch 52 has a drive component 53 fixed onto the cam shaft 48 and a driven component 54 that normally rotates freely on the cam shaft. Projecting externally of the driven clutch component 54- there is a clutch operating arm 55 which effects disen gagement of the clutch mechanism when stopped by a lug 56 on a shiftable slide bar 57. The slide bar 57 is supported on the ends of pins 58 that are mounted at their other ends on the adjacent one of the upright plates 13. A spring 59 urges the slide bar 57 to the left, facing FIG. 1, to position lug 56 in the path of the clutch operating arm 55. The driving clutch component 53 may be driven by suitable gears and a belt 61 from the driving shaft 23.

Pivotally connected to one end of the slide bar 57 is an armature 62 of a solenoid 63 that operates to disengage lug 56 from the clutch operating arm 55. This solenoid 63 is energized momentarily upon the depression of a push button switch, diagrammatically illustrated in FIG. 1 and designated generally by the numeral 64. When the clutch 52 is activated, cam 46 is rotated through one revolution which retracts the homing slide 36 and then releases it for return to stop position in time to engage the other of the abutment pins 4-4, thus limiting rotation of wheel 16 to a one-half revolution.

A second stop member or slide 65 is provided to stop the read-in wheel 16 and thus the print wheel 1% during the time that stop slide 36 is retracted. The slide 65 has a reduced end 66 that is positioned to engage between any two adjacent ones of the teeth of read-in gear 16 when the slide is released. A spring 67 urges the stop slide 65 into engagement with the teeth of the read-in gear 16 and is restrained normally by a releasable holder or armature 68 of a normally energized solenoid 69. As shown in FIG. 7, each of the slides 65 is provided with a stop member or armature 68, respectively, of solenoids 1 to 8 for individual release of the slides.

A cam 76 is fixed onto the cam shaft 48 and is engaged by a cam follower '72 on one end of an arm 74 of a bail that operates to retract all of the slides 65 simultaneously. Carried by and extending between the arms of the bail is a rod 78 that engages abutrnents 80 provided on the stop slides 65. A spring 82 acts to pivot the bail in a direction to maintain the cam follower 72 in engagement with the cam 70. Another cam 84, fixed onto the cam shaft 48 operates a lever 86 to trip the clutch 20, the lever being biased by a coil spring 85 to hold a cam follower roller 87 in engagement with the cam 84 and to hold an arm 83 of the lever 86 in engagement with a roller 89 carried by the slide 27, as shown in FIG. 2. The arrangement is such that a dwell in cam 84 delays the tripping and thus the engagement of clutch 20 until after the homing slide 36 has retracted to the point of clearing the abutment pin 42.

Mounted on one of the upright plates 13 is a timer or distributor switch 88, which is diagrammatically illustrated in FIG. 7a as comprising ten radially spaced, normally closed pairs of switch contacts which are respectively representative of the numeric digits to 9 of the decimal system and thus correspond to the printing elements on each of the print wheels 19. The switch contacts 0 to 9 are mounted on a suitable support and surround the driven shaft 18 on which there is fixed a rotary switch operator 90. The switch operator 90 has a home position corresponding to the home positions of the print wheels 16 and rotates one revolution following engagement of the one revolution clutch 52. During rotation, the switch operator 9% successively engages and opens all of the switches t to 9 inclusive. Preferably, the pairs of switch contacts 0 to 9 are radially spaced apart Within 180, or such that they are all opened during the first one-half revolution of the rotary switch operator 90. Further, the operator 9%) is preferably semi-circular in configuration, as shown, so as to hold the switches open during the first one-half revolution of the operator.

With particular reference to FIG. 711, there is diagrammatically illustrated a plurality of manually operable switches, designated generally by the numeral 92, for selecting the printing elements to be presented to the printing platen 38. The switches 92 are arranged as a matrix for disposition, preferably beneath a keyboard (not shown) such as the keyboard of a business or bookkeeping machine for key operation of the switches. The vertical rows of switches, designated 1 to 8, correspond to the columns 'or denominations, and also, of course, correspond respectively to the print wheels 10. The switches of each denomination, designated 0 to 9, are respectively representative of the numeric digits on corresponding ones of the print wheels 10 and also correspond to the timer switches 0 to 9 inclusive. Any suitable keyboard may be used, such as the well known type having mechanism that prevents the depression of more than one key of each column or denomination at a time by releasing a depressed key when another of the same column is depressed as shown and described in the patent to Thomas M. Butler No. 2,629,549.

The corresponding contacts of each denominational row of the switches 92 are electrically connected together, such as by busses 94 which are in turn, respectively, connected to the respective common terminals 96' of a plurality of gang operated switches 98 having normally closed contacts 100 and normally open contacts 101. Contacts 100 are respectively connected by leads to the corresponding ends of the solenoids 1 to 3 which have their other ends connected to a bus 102 that is in turn connected by a lead 104 to one of the output terminals of a bridge rectifier 105. The other and corresponding contacts of the switches 92 are connected electrically by busses 106 which in turn are respectively connected to the fixed contacts of the corresponding ones of the timer switches 0 to 9 inclusive. The other ones of the timer contacts 0 to 9 are connected electrically to a bus 107 which in turn is connected by a lead 108 to the other one of the output terminals of the bridge rectifier 105. Thus, all of the solenoids 1 to 8 are normally energized and the ones that will be de-en'erg'ized on rotation of the timer switch operator 90 will be determined by which of the selective keyboard operated switches 92 are closed. When the solenoids 1 to 8 are de-energized, the springs 67 thrust the stop slides 65 into engagement with the teeth of the read-in Wheels 16 to stop the print wheels 10 at the proper times to present those ones of the print elements to the printing platen 38 that correspond to the depressed ones of the keyboard switches 92.

Since there is the ever present possibility that one or more of the print wheels 10 will not be stopped, because of mechanical limitations, or other reasons, in the positions designated by the closed keyboard switches 92, there is provided in accordance with the inventiona verification system to check the closed ones of the keyboard switches 92 against the positions assumed by the print wheels 10, and, accordingly, control operation of the printing platen 38. The positions of the print wheels 10 are at all times represented respectively by a plurality of rotary columnar switches 1 to 8 which are diagrammatically illustrated as each comprising a plurality of radially spaced fixed contacts 0 to 9 that correspond respectively to the numeric digits or printing elements on the print wheels 10, and a rotary contact 110. All of the corresponding ones of the contacts 0 to 9 are connected by like designated leads to the horizontal busses 106 of the keyboard switches 92. The rotary contacts 110 are respectively driven from the read-in wheels 16, such as by gearing, and thus rotate in synchronized relation with the print wheels 10. Normally, all of the rotary switches 110 are at their home positions, as shown in FIG. 7.

Further in accordance with the invention, there is provided a pair of rotary scanner switches 112 and 114 which function to successively connect the columnar rows of keyboard operated switches 92 to the columnar rotary switches 1 to 8 that represent the positions of the rotate with cam shaft 48. The ring-like outer contact 115 is interrupted to receive the fixed contacts 1 to 8 which are arranged between the ends of contact 115 in numerical order with respect to the direction of rotation of contact 116. The rotary contact 116 is shown in its home or starting position and rotates through an angle of about 114 before it starts to wipe the fixed contacts 1 to 8.

The fixed contacts '1 to 8 are respectively connected by leads to the normally open contacts 101 of switches 98 and thus are connectable to the busses of the columnar keyboard operated switches 92. A cam 118 on cam shaft 48 operates immediately following completion of the positioning of the print wheels 10 to open the contacts 100 of the read-in circuit and close the contacts 101 of the platen control circuit. The bus 113 of scanner switch 112 is connected by a lead 120 to the coil of a relay 122 that controls the printing platen 38, the relay coil also being connected to the bridge rectifier 105 through a thyratron 124 that provides instant opening of the circuit to prevent operation of the platen 38 in the event that proof of verification fails. The provision of the gang switches 98 including contacts 100 and 101 operated by timing cam 118 provides a direct and quick change-over from the read-in circuit to the verification circuit.

The other scanner switch 114 is similar to scanner switch 112 and has radially spaced fixed contacts 1 to 8 and a rotary contact 128 together with an inner common contact or bus 113' and an outer ring-like contact or bus 115'. Fixed onto the cam shaft 48, the rotary contacts 116 and 128 rotate together from a common starting point or home position, as indicated. The fixed contacts 1 to 8 of the scanner switch 114 are respectively connected by leads to the rotary contacts 1 to 8 of the rotary switches 108 and the bus 113 of scanner switch 114 is connected by a lead 130 to the power source or rectifier bridge 105. A timing cam 132 on cam shaft 48 closes a switch 133 to operate the platen 38 provided that relay 122 is closed, which is the case, of course, if verification is effected.

An indicated, the relay 122 is normally energized, the circuit of the relay coil including a lead 134 that connects together the common contacts, 115, 115', of the scanner switches 112 and 114. Also, the circuit is normally maintained closed during the wiping of contacts 1 to 8 of the scanner switches by arranging the contacts 1 to 8 such that the rotary contacts 116 and 128 bridge adjacent ones of the contacts 1 to 8. The rotary contacts 116 and 128 rotate together, successively engaging their respective contacts 1 to 8, to keep the circuit of the platen relay 122 closed, providing that all of the print wheels 10 are in their selected or intended positions. In the event that one or more of the wheels 10 are not in positions corresponding to the indexed ones of the keyboard switches 92, the circuit of the coil of relay 122 will be broken before the timer switch 132 closes, thereby preventing operation of the printing platen 38.

Operation In the operation of the printing apparatus, the machine operator, by means of the keyboard switches 92, first closes those ones of the switches 92 that are electrically representative of the digits of the number to be printed. For example, if the number to be printed is, say, 11.11, the operator would, of course, depress the 1 key of each of columns 1 to 4 inclusive. The operator then depresses the starter switch 64, illustrated in FIG. 1, and starts a cycle of operation, which includes the reading in of the indexed number into the print wheels 10, a control operation to verify that the number in the print wheels 10 is the number indexed on the keyboard, and the printing operation if verification is efiected. When the starter switch 64 is closed, the solenoid 63 is energized and trips the one revolution clutch 52, which couples the cam shaft 48 to the driving shaft 23 to rotate cams 46, 70, 84, 118 and 132. The cam 46 retracts the homing slides 36 and at about the same time, the cam 70 disengages from the stud 72 to release the stop slides 65 to their respective electrically operated holders or solenoid armatures 68. Only those ones of the slides 65 corresponding to the indexed ones of the keyboard switches will be held retracted, the remaining slides returning to hold their respective read-in wheels against rotation just prior to re traction of the homing slides 36. Cam 84 has a dwell to effect a slight delay to allow the homing slide 36 to clear stud 42 and then operates lever 86 and trips clutch 20 whereupon the driven shaft 18 is coupled to the driving shaft 23'. As a consequence, the keyboard selected readin wheels 16, timer switch operator 90, print wheels 10, and the rotary switches 110 rotate. As the switch operator 90 of the distributor 88 rotates, it successively opens its associated switches 0 to '9 inclusive and deenergizes those ones of the solenoids 1 to 8 that are in closed circuit which, in this instance, are the 1 switches of columns 1 to 4. As a result, the stop slides 65' of columns 1 to 4 are released by the de-energized solenoids and the springs 67 thrust the stop slides 65 into engagement with and stop the corresponding read-in wheels 16 and thus stop the corresponding print wheels 10 with their printing elements 11.1'1 presented to the platen 38. When the stop slides 65 engage the read-in wheels 16-, the slip clutches 28 yield to allow the driven shaft 18 to continue to rotate until the one-half revolution clutch 20 disengages.

Closely following the de-energization of the solenoids of columns 1 to 4, the timer cam 118 actuates the gang switches 98, which breaks contacts to de-energize the read-in circuits and makes contacts 101 to energize the verification system circuits. At about this time, the scanner switches 116 and 128 scan their contacts 1 to 8, they successively connect each of the columns 1 to 8 of the keyboard switches 92 to the switch members of the columnar switches through the relay 122 that controls the circuit of the platen 38. Since the positions assumed by the columnar switch members 110 correspond to the positions assumed by the print wheels 10, completed circuits through the keyboard switches 92 and the corresponding rotary columnar switches constitute a verification that the print wheels 10 are correctly positioned. Each of the circuits tested include the control solenoid 122 which controls the circuit of the platen 38- and must remain energized if printing is to be efiected. Thus, if for some reason one or more of the print wheels 10 is not stopped in proper position, failure of verification will be indicated by de-energization of solenoid 122 and the consequential prevention of the printing operation of the platen 38. V

The above mentioned operations of reading the keyboard indexed number into the print wheels 10, verifying the positions of the print wheels, and the printing of the number all occur within one-half revolution of the cam shaft 48. During this time, cam 46 has rotated a complete revolution and has stopped by reason of clutch 52 being disengaged when the clutch operating arm 55 engaged the stop lug 56 which returned to normal position on release of the push button switch 64. After a slight dwell efiected by cam 84, to allow for the printing operation, the cam 84, through lever 86, again trips clutch 20 allowing the read-in wheels 16 and, thus, the corresponding print wheels 10 to restore to home positions.

The following description traces the circuitry through the lowest, or units denomination and assumes that the 1 key has been depressed to close the corresponding one of the keyboard switches 92. Rotation of the distributor switch operator 90 opens all of the distributor switches 0 to 9 and in this instance the opening of switch 1 breaks the following circuit: Line 108 from one side of the power source, the bus 107 of distributor 88, distributor switch '1, keyboard switch 1 of column 1, bus 94 of column 1 connected to the common terminal 96 of gang switches 98, solenoid 1, bus 102, and lead 104 to the other side of the power source. As above described, the

breaking of the circuit releases the stop slide 65-, which then normally functions to stop the read-in wheel 16 to, in turn, stop print wheel in position to present the 1 printing element to the platen 38. This is closely followed by the timer cam 118 actuating the gang switches 98 to engage contacts 101 whereby the following verification circuit is completed: From the power source through lead 130, bus 113', scanner switch member 128, the scanner 1 cont-act through its lead to the rotary contact 110 of the column 1 rotary switch, contact 1 of the column 1 switch, lead 1 to the 1 switch of column 1 of the keyboard switches 92 through the indexed 1 switch of column 1 of the keyboard switches to the common terminal of the respectively connected column 1 switch unit of the gang transfer switch 98, the 1 switch of the now transferred gang switches 98, the 1 contact of the scanner switch 112, rotary contact 116 of scanner switch 112, bus :113, lead 120 to the coil of relay 122 and through the thyratron 124 to the other side of the line. The verification or proving of the rotary switch settings of each successive column against the values indexed in the corresponding successive columns of the keyboard switches is continued with the progression of the scanner switch assembly. If the circuit is retained completed throughout the scanning action, verification of the proper position of the print wheels is established as indicated by relay 122 remaining closed to allow operation of the printing platen.

From the foregoing description, it will now be appreciated that we have provided for a high speed printing apparatus having differentially positionable print wheels, an improved control system for selectively controlling the positions of the wheels from keyboard operated switches. By determining the amount to be printed from selectively operableskeyboard switches, it will he understood that high speed reading of the amount indexed into the keyboard and then into the print wheels is effected immediately following the closing of the read-in cycle switch. Further, it will be appreciated that we have provided an improved printer control system involving a verification function by means of which the printing operation is prevented unless the printing elements presented for printing by the print wheels agrees with the information or amount indexed into the keyboard switches. .In addition we have provided for immediate initiation of the verification system upon completion of the read-in operation to avoid delay in the printing operation.

' While we have shown and described our invention in considerable detail, it will be understood that many variations may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1; In a printing system, a rotatable print wheel having printing elements spaced around the periphery thereof, a normally retracted electrically operated stop member operable when activated to stop said print wheel to position one of the print elements at a print line, a printing platen cooper-able with said print wheel, electrically operated means controlling operation of said platen, a plurality of key operated switch members respectively representative of the printing elements on said print wheel and electrically connected to activate said stop member, only one of said switches being closable at a time, a second plurality of switch members respectively representative of the printing elements on said print wheel and connected respectively in circuit with said first plurality of switchmembers and with said electrically operated stop -member, a rotary switch actuator rotatable in synchronized relation with said print wheel to successively actuate said second plurality of switch members, a rotary storage switch member electrically connected to said electrically operated means and to said key operated switch members and rotatable in synchronized relation with said print wheel, a plurality of contact members cooperable with said rotary switch member, said plurality of contact members respectively representative of the printing elements on said print wheel and respectively electrically connected to said key operated switch members, a switch member controlling the circuit of said electrically operated stop member and also the circuit of said electrically operated means, said switch member normally closed in the circuit of said electrically operated stop member, and a timing cam operable to close said switch member in the circuit of said electrically operated means following the stopping of said print wheel by said stop member.

2. In a printing system, a one revolution print wheel having printing elements on and spaced around the periphery thereof, means operable to initiate rotation of said print wheel, a stop member operable to stop said print wheel to present one of the printing elements to a print line, electrically operable means to actuate said stop member, a plurality of key operated switch members respectively representative of the printing elements on said print wheel and electrically connected to said electrically operated means, only one of said switch members being closable at a time, a second plurality of switch members respectively representative of the printing elements on said print wheel and connected respectively in circuit with said first plurality of switch members and with said electrically operated means, a switch actuator operable to successively actuate said second plurality of switch members and rotatable in synchronized relation with said print wheel, a switch member having a plurality of contact members respectively representative of the printing elements on said print wheel and respectively connected to said key operated switch members, a switch contact member rotatable in synchronized relation with said print wheel to contact the one of said contact members corresponding to the print wheel printing element presented to the print line, a switch member operable to connect said rotatable contact member in circuit with said key operated switch members to compare the print element representatively entered in the key operated switch with the print element presented to the print line.

3. In a printing system, a normally rotating print wheel having printing elements on and spaced around the periphery thereof, printing means activatable to cooperate with said print wheel, a stop member operable to stop said print wheel to present one of the printing elements to a print line, electrically operable means to actuate said stop member, a plurality of key operated switch members respectively representative of the printing elements on said print wheel and electrically connected to said electrically operated means, only one of said switch members being closable at a time, a second plurality of switch members respectively representative of the printing elements on said print wheel and connected respectively in circuit with said first plurality of switch members and with said electrically operated means, a switch actuator operable to successively actuate said second plurality of switch members and rotatable in synchronized relation with said print wheel, a switch member having a plurality of contact members respectively representative of the printing elements on said print wheel and respectively connected to said key operated switch members, a switch contact member rotatable in synchronized relation with said print wheel to stop on the one of said contact members corresponding to the printing element presented to the print line, a switch member operable to connect said rotatable contact member in circuit with said key operated switch members to compare the printing element entered in the key operated switch member with the printing element presented to the print line, and a signal operable mutually by the closed one or" said key operated switch members-and the engaged corresponding ones of said plurality of contact members and operatively connected to actuate said printing means.

4. In a printing apparatus having denominational print wheels differentially positionable by electrically operable means to present printing elements of the wheels to a printing platen, a control system for controlling the platen comprising an electrically operable control member for operative connection to the platen, a plurality of selectively operable denominational rows of storage switch members with the switch members of each row respectively representative of the digits of the decimal system and operable to control the electrically operable means, switch means responsive to the positions of the selected print Wheels, and switch means responsive to the positions of the selected storage switches and electrically connected to said first switch means mutually to control operation of said electrically operable control member.

5. In a printing apparatus, a rotatable print wheel having printing elements to 9 on and spaced around the periphery thereof, an electrically operated platen cooperable with said print wheels, a switch member controlling operation of said platen, a normally retracted electrically operable stop member operable when activated to stop said print wheel to present a selected one of the print elements thereon to said platen, a plurality of switch members representative respectively of the printing elements 0 to 9 on said print wheel and operatively connected to said stop member, an actuator arranged to successively actuate said plurality of switch members and rotatable with said print wheel, a second plurality of selectively operable switch members representative respectively of the printing elements 0 to 9 on said print Wheel and connected respectively to said first plurality of switch members, a switch member rotatable with said print wheel and electrically connected to said selective switch members, a scanner switch member electrically connected to scan said switch member, and a second scanner switch member electrically connected to scan said selective switch members, said scanner switch members electrically connected to and for mutually controlling said platen controlling switch member.

6. In a printing apparatus, electrically operated impression means, a plurality of print wheels respectively representative of the denominations of the decimal system and rotatable relative to each other, said print wheels each having a plurality of print elements on the periphery thereof respectively representative of the digits 0 to 9,

means operable to drive said print wheels, individual slip clutches respectively connecting said print wheels to said drive means, a plurality of electrically operated normally inactive stop members operable when activated to respectively stop said print wheels to present preselected ones of the print elements to said impression means, a plurality of settable switch members operatively connected respectively to said stop members, said settable switch members having groups thereof respectively corresponding to the denominational print wheels and the switch members of each group respectively representative of the print elements 0 to 9, a movable scanner switch member in circuit with and operable to scan all of the settable switch members to efiect activation of said stop members corresponding to the set ones of said settable switch members, a plurality of scanner switch means connected in circuit respectively with said groups of settable switch members, denominational scanner switch means in circuit with said switch means and with said selectable switch members, electrically operated imprese sion means cooperable with said print wheels, and an electrically operated switch controlling said impression means and in circuit with said denominational switch means, said plurality of scanner switch means and said settable switch members.

7. In a printing apparatus having an electrically operated impression means and a corresponding plurality of print wheels selectively positionable by a plurality of groups of settable switch members with the groups representative of the denominations of the decimal system and the switch members of each group representative of the digits 0 to 9, a verification system to operatively connect the settable switch members to the impression means comprising a plurality of scanner switch members to rotate respectively with the print wheels and representative respectively of the positions of the wheels, a denominational scanner switch member electrically connected to each of said plurality of scanner switch members, a second denominational scanner switch member for connection respectively to the groups of settable switch members and connected in circuit to said first-mentioned scanner switch member, and an electrically operated switch member to control the impression means and operatively connected to and controlled by said denominational scanner switch members.

References Cited in the file of this patent UNITED STATES PATENTS 2,699,857 Wales Jan. 18, 1955 2,796,830 Hilton June 25, 1957 2,906,200 Pfleger Sept. 29, 1959 

1. IN A PRINTING SYSTEM, A ROTATABLE PRINT WHEEL HAVING PRINTING ELEMENTS SPACED AROUND THE PERIPHERY THEREOF, A NORMALLY RETRACTED ELECTRICALLY OPERATED STOP MEMBER OPERABLE WHEN ACTIVATED TO STOP SAID PRINT WHEEL TO POSITION ONE OF THE PRINT ELEMENTS AT A PRINT LINE, A PRINTING PLATEN COOPERABLE WITH SAID PRINT WHEEL, ELECTRICALLY OPERATED MEANS CONTROLLING OPERATION OF SAID PLATEN, A PLURALITY OF KEY OPERATED SWITCH MEMBERS RESPECTIVELY REPRESENTATIVE OF THE PRINTING ELEMENTS ON SAID PRINT WHEEL AND ELECTRICALLY CONNECTED TO ACTIVATE SAID STOP MEMBER, ONLY ONE OF SAID SWITCHES BEING CLOSABLE AT A TIME, A SECOND PLURALITY OF SWITCH MEMBERS RESPECTIVELY REPRESENTATIVE OF THE PRINTING ELEMENTS ON SAID PRINT WHEEL AND CONNECTED RESPECTIVELY IN CIRCUIT WITH SAID FIRST PLURALITY OF SWITCH MEMBERS AND WITH SAID ELECTRICALLY OPERATED STOP MEMBER, A ROTARY SWITCH ACTUATOR ROTATABLE IN SYNCHRONIZED RELATION WITH SAID PRINT WHEEL TO SUCCESSIVELY ACTUATE SAID SECOND PLURALITY OF SWITCH MEMBERS, A ROTARY STORAGE SWITCH MEMBER ELECTRICALLY CONNECTED TO SAID ELECTRICALLY OPERATED MEANS AND TO SAID KEY OPERATED SWITCH MEMBERS AND ROTATABLE IN SYNCHRONIZED RELATION WITH SAID PRINT WHEEL, A PLURALITY OF CONTACT MEMBERS COOPERABLE WITH SAID ROTARY SWITCH MEMBER, SAID PLURALITY OF CONTACT MEMBERS RESPECTIVELY REPRESENTATIVE OF THE PRINTING ELEMENTS ON SAID PRINT WHEEL AND RESPECTIVELY ELECTRICALLY CONNECTED TO SAID KEY OPERATED SWITCH MEMBERS, A SWITCH MEMBER CONTROLLING THE CIRCUIT OF SAID ELECTRICALLY OPERATED STOP MEMBER AND ALSO THE CIRCUIT OF SAID ELECTRICALLY OPERATED MEANS, SAID SWITCH MEMBER NORMALLY CLOSED IN THE CIRCUIT OF SAID ELECTRICALLY OPERATED STOP MEMBER, AND A TIMING CAM OPERABLE TO CLOSE SAID SWITCH MEMBER IN THE CIRCUIT OF SAID ELECTRICALLY OPERATED MEANS FOLLOWING THE STOPPING OF SAID PRINT WHEEL BY SAID STOP MEMBER. 